Dubuque turned 67,000 plastic bottles into floating islands for wildlife

Dubuque, Iowa celebrated its 67,000th recycled plastic bottle on 2017 when 14 floating islands were installed in the Bee Branch Creek as part of a creek restoration project. The islands were designed to provide more than just greenery, but also to protect the creek, improve water quality, and create habitats for various wildlife.

Dubuque had been grappling with flooding issues for years, particularly in the 7-square-mile Bee Branch Watershed where more than half of the city's residents lived or worked. Flash floods had caused damage to 1,300 homes and businesses, affecting buildings, roads, and stormwater infrastructure. The city responded by daylighting the Bee Branch creek, which had been buried underground for about a century.

The restored creek became the site of an unusual experiment involving 14 floating islands, each totaling 2,674 square feet. These islands were constructed from 67,000 recycled BPA-free water bottles, along with native plants and driftwood. Stainless-steel cables anchored them to the creek bed, allowing them to shift with the changing water levels and flow directions.

The floating islands perform various ecological functions. They interrupt wave energy, reducing erosion along the creek's edges, and act as barriers to slow water movement, allowing suspended sediment to settle and keep the water clear. Additionally, plant roots and floating structures provide space for biofilms, microorganisms that can break down pollutants. The roots below the water offer shelter for fish, juvenile aquatic species, insects, and crustaceans, while birds use the islands for resting and potential nesting.

However, the project shows that nature-based infrastructure needs ongoing maintenance. The islands are regularly checked for buoyancy, vegetation, and anchoring systems. Regular inspections have found that most plants are thriving, but some have had to be replaced due to animal interference, and parts of protective fencing needed repairs.

Dubuque's experience demonstrates that careful site selection, native vegetation, durable materials, secure anchoring, and regular maintenance are crucial factors for communities considering similar projects. The floating islands have transformed the creek into a working part of urban ecology, proving that flood infrastructure can create room for nature.